Engine intake regulating means



ENGINE INTAKE REGULATING MEANS Filed NOV. 2, 1933 Ja a I T: I J I -50 2 I INVENTOR.

mu 4 M ATTORNEY Patented June 1, i937 UNIT El) "STATES ENGINE ancnmmo MEANS 'lhorp Hiscock; Seattle,

Wasln, assignor, by

memo assignments, to United Air Lines Transport Corporation, a corporation of Delaware ApplicationNovember 2, 1933, Serial No., 696,350

r Claims. (c1. 123-119)v This invention relates to internal combustion engines and more particularly to the regulation of the fuel mixture supplied to such engines; especially such as airplane engines which are subjected to substantial changes in atmospheric pressure.

One of the objects of my invention is to con trol the pressure in the carburetor intake.

- Another object of my invention is to control the air density in the engine intake.

' till another object of my invention is to automatical ly maintain constant pressure at a predetermined maximum value in the carburetor intake. Further and other objects and advantages will be apparent from the specification and claims and from the accompanying drawing which illustrates what is now considered the preferred embodi'ment.

The fi ure shows a diagrammatical view of my carburetor intakepressure and'temperature re ulator. 1 a

Variations in atmospheric pressure' and in temperature have long been known to aflect the 25 action or the carburetor of an internal combustron engine. In orderv to have the carburetor of an engine which is required to operate under these varying atmospheric conditions perform satisfactorily, it is thereby changing the fuel-air ratio. Such means are called mixture controls and are operated manually to secure the desired engine performance.

According to the present invention, means are provided to automatically maintain the pressure and temperature of the air conducted to the carburetor intake substantially constant at predetermined values. By thus regulating the pres- 40 sure and temperature'of the carburetor intake air, the fuel air ratio is, with a properly designed carburetor,- automatically maintained constant.

By limiting the predetermined maximum pressure in the carburetor intake, the maximum 45 power output and the maximum combustion chamber pressure are limited to a predetermined safe maximum. This becomes of special value when the engine is operating in an atmospheric pressure which, unless controlled, would produce 50 such a. high pressure in the carburetor intake that excessive pressm'es would be developed in the engine.

The invention disclosed in the present appli cation is shown as applied to a convent onal ra- 55 dial airplane motor :0 with a supercharger provided with means for 30 changing the quantity of liquid fuel supply,

blower l2 drivenfrom engine crankshaft 8 by gears 6 and taking fuel mixture from the carburetor H through conduit l6 anddelivering it to difiuser l8 and thence through conduits to the various engine cylinders. r 5

Air is supplied to the carburetor through a conduit 22 having branches 24 and 26 for leading hot and coldair respectivelythereto. A valve 28 is placed at the junction of conduits 24 and 26 and ispivoted so that it may regulate the ratio of hot to cold air admitted to conduit 22 .and thereby regulate the resultant temperature of the air in that conduit. v

A valve 30 is placed in conduit 22 and is adapted to, restrict the free areaof that conduit and therebyregulate the pressure in that conduit especially between the valve and the carburetor. while the engine isoperating and air is being. conducted through the conduit.

A pressureregulating device, indicated generally at32, is provided to operate the valve 30. The pressure regulating device may be any device capable of giving a large resultant move-.- ment for a small change in pressure. In the modification shown, this pressure regulator comprises an evacuated metallic bellows 3| usually balanced against collapse by means of a spring,

-' not shown. placed inside the bellows. This bellows is placed to act directly against a similar bellows 36 connected with the conduit 22' between valve and the carburetor. These two. bellows act on a lever 38 to operate pistons III and '42 which control-the admission of oil under pressure to opposite sides of the piston 44. Oil under pressure, usually from the engine lubricating sysr tem, is led into conduits 46 and 4a, and the pipe 3 50 conducts oil back to the engine sump or other storage tank. j Bellows 34 and 36 actingagainst each other balance out any change Vin externalpressure so 0 that the pressure regulator. is unafiected by any change in atmospheric pressure such as that due 'to altitude. Any change of pressure in conduit 22 operates bellows 36 and in turn the servo- 1 mechanism to operate valve 30- and return the pressure to the predetermined value.

In order to automatically maintain a constant fuel air ratio, it is necessary to automatically maintain a constant densityin the-carburetor intake. Although the pressureremains constant,

variation in the temperature of the intake air the fuel-air ratio suppliedby the' carburetor. In the embodiment shown,fI have provided means to regulate this temperature so that together with the pressure regulation, a substantially constant air density may be maintained. I have shown a temperature regulator represented generally at 52 in which a metallic bellows 54 actuates a servo mechanism similar to that described for the pressure regulator and which it is considered unnecessary to again describe in detail. The bellows 54 is connected with temperature responsive element 56 so that temperature changes operate the bellows and in turn the servo mechanism which, in turn, operates the valve 28 to control the proportions of cold-and hot air admitted to the carburetor intake. Difierences in atmospheric pressure would affect the action of the bellows 54 and in order to overcome the eifect of altitude changes on this bellows, it is-encased in an air-tight housing which is vented to the constant pressure area of the conduit 22. By this means, a constant pressure is maintained on the bellows 54 so that the temperature regulation is independent of atmospheric pressure. It is to be noted that the temperature and pressure in conduit 22 are regulated by the temperature and pressure in that conduit independent of any external conditions. Hence, when thelmechanism is set for any predetermined pressure and temperature, thatpressure and temperature is automatically maintained independent of changes of external pressure or temperature, engine speed or any other external condition within the limits for which the mechanism is designed.

While this device finds particular use in con-- nection with the regulation of the air intake it may also find other uses,

of a carburetor, such as the regulation of the pressure, temperature, or density of the ,air intake of a fuel in- -jection engine or other engines on which a similar regulation is of value;

' While I have explained this invention in connection-with what is now thought to be the preferred form of mechanism, it is to be .expressly understood that other mechanisms may be used and various modifications may be made. therefore, to be expressly invention is not limited to the specific mecha.-'

It is, understood that my nism' shown, but may be used in various other ways without departure from its spirit as shown by the following claims.

What I claim is:

1. In combination with 'an internal combustion engine, a carburetor therefor, .and an air intake for said'carburetor, means for maintaining the air'flowing through said carburetor to said engine constant at a predetermined density, said means comprising, means in said intake for regulating the pressure of the air in said intake, means responsive to changes in the pressure of thevair in said intake for controlling said regulating means to maintain said pressure constant at a predetermined value, means in saidintake for regulating the temperature of the air flowing therethrough, and means responsive to the temperature and pressure of the air in said intake for controlling said temperature regulating means to maintain the temperature of said air constant at a temperature corresponding to the pressure in said intake to provide aconstant air density.

2. In combination with an internal combustion engine, a carburetor'thereior, and an air intake for said carburetor, means for maintaining the air flowing through said carburetor to said engine constant at a predetermined density said means comprising, means in said intake ahead of said carburetor for regulating the pressure of the air in said intake, means responsive to changes in the pressure of the air in said intake for controlling said regulating means to maintain said pressure constant at a predetermined value, means in said intake ahead of said pressure regulating means for regulating the temperature of the air flowing through said intake, and means responsive to the temperature and pressure of the air between said pressure regulating means and said carburetor for temperature regulating means to maintain the temperature of said air constant at a temperature corresponding to the pressure in said intake to provide a constant air density.

3. In combination with an internal combustion engine, a carburetor therefor and an intake for said carburetor, means for maintaining the air flowing through said carburetor to said engine constant at a predetermined density, said means comprising, means in said intake ahead of said carburetor for regulating the pressure of the air in said intake, means responsive to flowing through said intake, and means comprising an expansible element surrounded by air of the pressure of the air in said intake between said carburetor and said pressure regulating means responsive to the temperature of the air in said intake for controlling said temperature regulating means to maintain the temperature of said air constant at a temperature corresponding to the pressure in said intake to provide a constant air density.

4. In an internal combustion engine, in combination, an air intake, and means for regulating the density of the air in said intake to maintain constant a predetermined air density, said means comprising, means responsive to the pressureof the air in said intake for controlling said pressure, and means responsive to the temperature of the air at said controlled pressure for controlling the temperature of the 

